Liquid detergent gel compositions having stability against separation



United States Patent LIQUH) DETERGENT GEL COMPQSKTIQNS HAV- INGSTABHJITY AGAINST SEARAT10N Martin E. Ginn, Dayton, Ghio, assignor toMonsanto Chemical Company, St. Louis, Mo, a corporation of Delaware N0Drawing. Filed Dec. 28, 1956, Ser. No. 631,027 13 Claims. (Cl. 252-135)The present invention relates to liquid detergent gel compositions. Theinvention likewise relates to detergent compositions which exhibitstability against phase separation and precipitation in the presence ofhigh concentrations of inorganic salts and of synthetic organicdetergent components.

In the operation of automatic washing machines and dishwashing machinesit is highly desirable to employ liquid detergent concentrates which canbe measured and pumped or flowed automatically from a supply tank. Suchsolutions contain high concentrations of inorganic salts, for example,phosphates and carbonates, in addition to active organic detergentcomponents. The solutions, therefore, readily separate into organic andaqueous phases as well as crystalline precipitates, particularly at lowtemperatures. Consequently, a pump-feed or gravity system cannot providea uniform detergent concentrate from such a mixture. In addition thehigh concentrations of inorganic components, such as phosphates whichare desirable for heavy duty purposes, cause crystallization whichresults in a loss of a part of the detergent composition and also causesplugging of the feed lines.

It has now been found that liquid detergent gel compositions containingan active organic detergent component and inorganic alkaline salts maybe stabilized by the combination therewith of a specific stabilizingcomponent.

The stabilizing components employed in the preparation of the presentaqueous detergent gels are polyelectrolytes which have been preparedfrom synthetic, organic, linear polymers by cross-linking. A preferredgroup of polymers are the vinyl polymers. These include homopolymers,such as those derived from acrylonitrile, and copolymers, such as maleicanhydride copolymerized with an olefinic compound, for example,ethylene, propylene or isobutylene.

A preferred cross-linked vinyl polymer is the reaction product offormaldehyde with hydrolyzed polyacrylonitrile. The hydrolysis of thepolyacrylonitrile is carried substantially to completion, such as byalkaline or acid hydrolysis as described in US. Patents 2,625,529 and2,727,835. Other vinyl polymers which have been found to have particularutility in forming cross-linked polymers having stabilizing action inaqueous detergent gels are the copolymers of maleic anhydride. Themaleic anhydride is copolymerized in substantially equimolar proportionswith other copolymerizable monomers of less than 5 carbon atoms, such asethylene, propylene, isobutylene, vinyl acetate or vinyl methyl ether.The above maleic copolymers are then cross-linked with a diamine or analkylene polyamine. The amines employed in this relationship are primaryor secondary amines having at least two carbon atoms, for example thealkylene polyamines. The polyamines which have been found to beparticularly useful include diethylene triamine, triethylene 3,060,l24Patented Oct. 23, 11932 tetramine, tetraethylene pentamine andpolyethyleneamine.

The above polymers and copolymers, either before or after cross-linkingare transformed into water-swellable forms having utility as stabilizersin the present detergent gels by reaction with a base, such as sodiumhydroxide, potasssinm hydroxide, ammonia or amines. In this way thesodium, potassium, ammonium or amine salts are formed. In order toobtain such salts the copolymers are reacted with the base or analkylamine, such as methyl, butyl and amylamine, cyclohexylamine or aquaternary ammonium hydroxide, such as phenyl trimethyl ammoniumhydroxide. The polymer is thus transformed into the amine or ammoniumsalt or the half amide.

The above modified polymers may first be cross-linked with across-linking agent, such as formaldehyde, a diamine or an alkylenepolyamine to obtain a gel-forming stabilizing agent containing a smallamount of cross-linking product by the above cross-linking agents. Thecrosslinking in the molar structure are due primarily'to amide linkages.The formaldehyde cross-linking reaction is primarily through residualamide groups in the hydrolyzed or partially hydrolyzed polymer, forexample, polyacrylonitrile. Another way of preparing effective liquiddetergent gel stabilizers is to begin with polyacrylamide which isutilized as a pure homopolymer for cross-linking with formaldehyde toobtain a gel-forming material.

The cross-linking of the above-described synthetic, organic linearpolymers results in the production of a waterswellable, gel-formingmaterial which is of utility in the manufacture of the present aqueousdetergent gels. The degree of cross-linking, as defined herein, is thepercent by weight of the cross-linking agent, such as the aboveformaldehyde or alkylene polyarnine based upon the weight of theoriginal polymer.

Hydrolyzed polyacrylonitrile which has been crosslinked withformaldehyde has been found to give particularly effective aqueousdetergent gels when the range of formaldehyde employed is from 0.01% to0.30% by weight of formaldehyde relative to the hydrolyzedpolyacrylonitrile. A more preferred range is from 0.01% to 0.20% byweight of formaldehyde. Acetaldehyde may similarly be used incross-linking the hydrolyzed polyacrylonitrile to obtain a gel-formingpolyelectrolyte. The cross-linked polyelectrolytes may be employed asvarious basic salts, such as the sodium, potassium, ammonium, or basicamine salts. The preferred salt is the sodium salt. An example of suchan amine salt is the isobutylamine salt.

The gel-forming polyelectrolytes employed as stabilizing agents in thepresent invention are characterized in having viscosities in the rangeof to 10,000 centipoises or more preferably from 1,000 to 8,000centipoises (Brookfield, 6 rpm.) measured on a solution containing 1.0weight percent of the material in water. For example, a preferred typeof sodium salt of the formaldehyde-crosslinked polymer of hydrolyzedpolyacrylonitrile has a viscosity of about 6,000 centipoises and a gelof isobutylenemaleic anhydride cross-linked with ethylene diamine, andemployed as the ammonium salt as a viscosity of 1,500 centipoises.

The proporiton of the cross-linked vinyl polymer employed in the presentaqueous detergent gel compositions is from 0.25% to 2.0% by weight ofthe said cross-linked trates.

- 3 vinyl polymer in the total detergent gel composition. A preferredrange is from 0.75% to 1.25% by weight.

The active detergent components employed in the present invention aresynthetic, organic detergents, preferably of the non-ionic type.However, minor proportions of other active detergent components such asthe alkaline salts of alkylaryl sulfonic acids may also be employed inthe present invention.

In the practice of the present invention, preferred nonionic detergentcomponents include alkylene oxide condensation products of highlybranched monohydric primary alcohols having the molecular configurationof an alcohol produced by the Oxo process from olefins of the classconsisting of polybutylenes and polypropylenes such as triisobutylene,tetrapropylene, tetraisobutylene, pentapropylene, pentaisobutylene andhex-apropylene. These condensation'products may contain on the averageof from 1 to 20 moles, preferably from to moles of condensed alkyleneoxide per mole of the said alcohol. The alkylene oxides employed havefrom 2 to 3 carbon atoms. The condensation products may also be madewith combinations of alky-lene oxides, such as by condensing isodecylalcohol with 8 moles of propylene oxide, followed by 6 moles of ethyleneoxide.

When polymer olefins such as polyisobutylene or polypropylene arereacted according to the Oxo reaction with carbon monoxide and hydrogenin the presence of a catalyst containing cobalt carbonyl, and thereaction products hydrogenated, a mixture of isomeric alcohols having awide boiling range is obtained. The alcohols may be manufactured by theprocess described in Bureau of Mines Report of Investigation No. 4270,dated June 1948. In .view of the presence of a number of isomers oftriisobutylone or tetrapropylene, for example, in the polymer olefinswhich are treated according to the 0x0 reaction and furthermore, sincethere is considerable isomerization, polymerizationand depolymerizationof the olefins due to the catalytic action, the resulting alcoholicproduct contains a large number of different alcohols, some of which arepolyhydric alcohols. By reason of the large number of compounds presentin the 0x0 reaction product it has so far been impossible to ascertainthe exact composition of this product. It has been found, however, thatthe fraction consisting substantially only of tridecyl alcohols boilingwithin the range 226 C. to 264 C. (ASTM dis- .tillation at atmosphericpressure) may be reacted with ethylene oxide to obtain mixed polyetherswhich have outstanding properties as a detergent component in thepresent invention.

Another preferred class of synthetic, organic detergents which mayconstitute all or part of the active component in the present aqueousdetergent gels includes alkylene oxide condensation products of otherhydroxy organic compounds such as alkylphenols. Preferred alkylphenolsare those having alkyl radicals of from 8 to 18 carbon atoms.- Thecondensation products of the said alkylphenols are prepared with analkylene oxide having from 2 to 3 carbon atoms, e.g., a condensationproduct may be prepared by first using ethylene oxide, and then furthercondensing with propylene oxide, or vice versa. Preferred condensationproducts of this type contain from 5 to alkylene oxide groups per moleof the said alkylphenols, for example 7 moles of ethylene oxidecondensed with one mole of nonylphenol.

Other detergent components may supplement the abovedescribed componentsin the present detergent concenbe considered as representative of lauricacid. Another source is the tall oil fatty acids, which may be obtainedby distillation from tall oil. The alkylolamide is formed by Typical ofthese types of detergents are the "alkylolamides having from 10 to 20carbon atoms in the acid radical. The alkylolamides may be derived fromthe reaction of the above fatty acids with an alkylolamine such asmonoor diethanolamine, monoor diisopropanolamine, or mono ordi-n-propanolamine.

Another group of auxiliary detergent components which may be employed inthe present invention is the class of aromatic sulfonates such as thesodium sulfonates of an alkylated aromatic hydrocarbon. These sulfonatesmay be prepared by condensing an aliphatic hydrocarbon having from 9 to18 carbon atoms, with an aromatic hydrocarbon selected from the classconsisting of benzene, toluene, and xylene, and thereafter sulfonatingthe product and neutralizing it to obtain the sodium, ammonium oralkylammonium salt. The preferred aromatic hydrocarbon member of thisgroup is benzene, .but the compounds obtained from toluene and xylenehave also been found to have desirable properties as surface-activecompositions. The alkyl group is preferably of about 10 to 12 carbonatoms average length, such as may be obtained from olefin polymers orkerosene. An olefin-polymer alkylate composition of this type isproduced by alkylating the aromatic hydrocarbon, with an olefinhydrocarbon averaging 9 to 18 carbon atoms in the molecule, andthereafter sulfonating and neutralizing the product. When kerosene isemployed as the source of the alkyl groups, the kerosene may bechlorinated and the aromatic compound alkylated therewith in knownmanner. Such compounds are described in U.S. 2,232,117 and U.S.2,232,118 to Kyrides.

In the formulation of the present aqueous detergent gels, a majorcomponent is an alkaline material selected from the group consisting ofinorganic phosphates, carbonates, silicates and combinations thereof.The said organic salts are preferably potassium salts, although sodiumsalts may also be employed, particularly in combina tion with thepotassium salts. The phosphate compounds must be chain polyphosphates.Such polyphosphates contain more than one phosphorus atom per molecule,as distinguished from orthophosphates which contain only one phosphorusatom per molecule. Chain polyphosphates are non-cyclic (and usuallylinear) phosphates, as distinguished from ring or cyclic phosphates suchas trimetaphosphate and tetrametaphosphate. Examples of the more commonchain polyphosphates are tetrapotassium pyrophosphate and potassiumtripolyphosphate, both of which can be obtained as essentially purecrystalline materials, and an amorphous polyphosphate known as potassiumhexametaphosphate or sodium hexametaphosphate.

The amorphous polyphosphates, also known as glassy phosphate, aregenerally characterized either in terms of mole ratio of K 0 (or Na o)to P 0 or in terms of average chain length, ii, of the polyphosphatemolecules in the glassy phosphate. For example, commercial sodiumhexametaphosphate has a mole ratio of Na O to P 0 of about 1.13, and anaverage chain length of about 15 phosphorus atoms. In general, any ofthe water-soluble glassy polyphosphates, which have mole ratios of Na Oor K 0 relative to P 0 ranging between about 5:3 and about 1:1(corresponding to a range of average chain length from 3 to severalthousands or higher) are suitable for use as the chain polyphosphateingredient of the present aqueous detergent gels.

Another ingredient which is preferably utilized along with theabove-described detergent compounds and chainpQIyphosphates in theaqueous detergent solutions preuse according to the present invention.However, other silicates, or mixtures of silicates, have an overall moleratio of Na Ozsio between about 1:1 and 1:4.

The carbonates employed are preferably the potassium carbonates such ascommercial pearl ash or modified potassium carbonates having variousdegrees of alkalinity. Minor amounts of additional ingredients, such asborax and potassium or ammonium borates, dyes, perfumes, etc., can alsobe incorporated into the liquid detergent. Additionally, the ultimateconcentrate mixture is preferably formulated so that an aqueous solutionof about 0.25 weight percent has a pH of between about 8 and about 11.

In making up concentrated detergent liquid gels according to the presentinvention, the aforementioned said ingredients should be utilized in thefollowing proportions: (1) 5% to 25% by weight of active detergentcompounds; (2) from to 50% of chain polyphosphate; (3) from 1% to 10% ofwater-soluble silicate (calculated on the basis of anhydrous material);and from 0.25% to 2.0% of the cross-linked polymer as the gelstabilizer.

The liquid formulations of the present invention contain from 30% to75%, and preferably from 40% to 65% by weight of Water based upon thetotal liquid detergent. Alcohols, such as ethanol and glycols, such asethylene glycol or propylene glycol may also be employed in the presentdetergent compositions, particularly to improve the compatibility of thevarious components over a wide range of temperature conditions. Theproportion of alcohol or glycol may be from 1% to 20% by weight.

The present products have been found to be of particular utility inautomatic washers as a liquid concen trate, which is readily pumpedthrough pipes and tubing into the washing chamber. These compositionsmay be stored for prolonged periods of time without separation intoorganic and inorganic layers. This is essential in the production of aliquid detergent which is to be utilized in small increments during along period of storage.

The following examples illustrate specific embodiments of the invention.

Example 1 A detergent gel product was prepared by mixing the followingcomponents in parts by weight:

Condensation product of 8.5 moles of ethylene oxide with 1 mole oftridecanol Water 52.5

This detergent product was found to be stable in storage without phaseseparation. In contradistinction, the same basic formulation without thesodium salt of formaldehyde-cross-linked hydrolyzed polyacrylonitrileexhibited phase separation five minutes after mixing.

In the above formulation the carboxymethylcellulose (0.7 degree ofsubstitution) is employed as a soil-suspending agent, which preventsredeposition of the soil removed from fabrics, etc. The reference 0.7degree of substitution indicates the degree of carboxymethylation of thecellulose, i.e., there are 0.7 carboxymethyl groups per anhydroglucoseunit of the cellulose. Carboxymethylcellulose when used in the aboveformulation without the sodium salt of formaldehyde cross-linkedhydrolyzed pol acrylonitrile has been found to be without stabilizingaction as required in the present high concentration liquid detergents.

In the present combination detergent it has been found that thestabilizing components such as the cross-linked reaction product offormaldehyde with hydrolyzed'polyacrylonitrile also aids in thedispersion of the carboxymethylcellulose, which ordinarily is verydifficult to incorporate into a built liquid detergent.

The following detergent compositions were prepared as further examplesof high concentration liquid detergent gels stabilized by the presenceof cross-linked polymers (proportions by weight).

Water 52.5

The above composition was found to be stable for a period of 20 dayswhen given an accelerated deterioration test at 50 C. The compositiondid not crystallize out nor exhibit any phase separation.

Example 3 Percent Condensation product of 8.5 moles of ethyleneoxide and3.0 moles of propylene oxide with 1 mole of tridecanol 8.5 Sodium saltof sulfonated dodecylbenzene 5.0 Isopropanolamide of lauric acid 1.5Potassium tripolyphosphate 30.0 Carboxymethylcellulose (0.7 degree ofsubstitution) 1.5 Sodium salt of formaldehyde-cross-linked hydrolyzedpolyacrylonitrile 1.0

Water 52.5

The above formulation was found to be stable for a period of 13 days inan accelerated stability test conducted at 50 C.

Example 4 Percent Condensation product of 4 moles of propylene oxide and10 moles of ethylene oxide with 1 mole of tridecanol 15.0 Potassiumtripolyphosphate 6.25 Sodium tripolyphosphate 6.25 Potassium carbonate15.0 Potassium silicate (1:2.1 K OzsiO ratio) 2.75

Carboxymethylcellulose (0.7 degree of substitution) 0.75 Sodium salt offormaldehyde-cross-linked hydrolyzed polyacrylonitrile 1.0 Gel ofcross-linked polymer of isobutylene-maleic anhydride (1:1 molarproportion) 0.5 Water 52.5

with 1 mole of tall oil 15.0 Potassium tripolyphosphate 30.0 Sodium saltof formaldehyde-cross-linked hydrolyzed polyacrylonitrile 1.25 Water53.75

The above detergent concentrate was stable at a 50 C. temperature for aperiod of six days.

Example 6 In order to demonstrate the inadequacy of conventionalcarboxymethylcellulose as a stabilizer for liquid detergent compositionsof high concentration, the following composition was prepared:

Percent Condensation product of 8.5 moles of ethylene oxide with 1 moleof tridecanol 15 .0 Potassium tripolyphosphate L. 30.0

Carboxymethylcellulose (0.7 degree of substitution) 3.0 Water 52.0

The above mixture, when subjected to the conventional agitation asutilized in the foregoing examples was found to separate immediatelyinto an aqueous and organic phase.

Carboxymethylcellulose (0.7 degree of substitution) 0.75 Sodium salt offormaldehyde-cross-linked hydrolyzed polyacrylonitrile 1.25 Water 53.0

The above detergent composition is intended particularly as an easilypumpable concentrate for dishwashing machines. This composition wasfound to be stable for a period of five days in a phase separation testconducted at 50 C.

What is claimed is:

1. An aqueous liquid detergent gel consisting essentially of 40% to 65%by weight of water and to 25% of a synthetic, non-ionic, organicdetergent compound in com bination with to 50% of an alkaline substanceselected from the group consisting of sodium and potassium chainpolyphosphates silicates and combinations thereof together with 0.25% to2% of a cross-linked vinyl polymer having a viscosity of from 100 to10,000 centipoises.

2. An aqueous liquid detergent gel consisting essentially of 40% to 65%by weight of water and 5% to 25% of a synthetic, non-ionic, organicdetergent compound in combination with 10% to 50% of an alkalinematerial selected from the group consisting of sodium and potassiumchain polyphosphates, silicates and combinations thereof together with0.25% to 2% of a cross-linked vinyl polymer having a viscosity of from1,000 to 8,000 centipoises. a

3. An aqueous liquid detergent gel consisting essentially of 40% to 65by weight of water and 5% to 25% of a synthetic, non-ionic, organicdetergent compound in combination with 10% to 50% of an alkalinesubstance selected from the group consisting of sodium and potassiumchain polyphosphates, silicates and combinations thereof together with0.75% to 1.25% of a cross-linked vinyl polymer having a viscosity offrom 100 to 10,000 centipoises.

4. An aqueous liquid detergent gel consisting essentially of 40% to 65by weight of Water and 5% to 25 of a synthetic, non-ionic, organicdetergent compound in combination with 10% to 50% of an alkalinematerial selected from the group consisting of sodium and potassiumchain polyphospha-tes, silicates and combinations thereof, together with0.75 to 1.25% of a cross-linked vinyl polymer having a viscosity of from1,000 to 8,000 centipoises.

5. An aqueous liquid detergent gel consisting essentially of 40% to 65by weight of water and 5% to 25% of a synthetic, non-ionic, organicdetergent compound in combination with 10% to 50% of an alkalinematerial selected from the group consisting of sodium and potassiumchain polyphosphates, silicates and combinations thereof, together with0.25% to 2% of a sodium salt of formaldehyde-cross-linked hydrolyzedpolyacrylonitri-le having a viscosity of from 100 to 10,000 centipoises.

6. An aqueous liquid detergent gel consisting essentially of 40% to 65by weight of water and 5% to 25 of a synthetic, non-ionic organicdetergent compound in combination with 10% to 50% of an alkalinematerial selected from the group consisting of sodium and potassiumchain polyphosphates, silicates and combinations thereof, together with0.25% to 2% of a potassium salt of formaldehyde-cross-linked hydrolyzedpolyacrylonitrile having a viscosity of from to 10,000 centipoises.

.7. An aqueous liquid detergent gel consisting essentiallyof 40% to 65by weight of water and 5% to 25 of a synthetic, non-ionic organicdetergent compound in combination with 10% to 50% of an alkalinematerial selected from the group consisting of sodium and potassiumchain polyphosphates, silicates and combinations thereof, together with0.25 to 2% of a polymer of isobutylene and maleic anhydride cross-linkedby reaction with an alkylene polyamine, and having a viscosity of from100 to 10,000 centipoises.

8. An aqueous liquid detergent gel consisting essentially of 40% to 65by weight of water and 5% to 25 of a synthetic, non-ionic, organicdetergent compound in combination with 10% to 50% of an alkalinematerial selected from the group consisting of sodium and potassiumchain polyphosphates, silicates and combinations thereof, together with0.25% to 2% of a polymer of ethylene and maleic anhydride, cross-linkedby reaction with an alkylene polyamine,-and having a viscosity of from100 to 10,000 centipoises.

9. An aqueous liquid detergent gel consisting essentially of 40% to 65%by weight of water and 5% to 25% of a synthetic, non-ionic, organicdetergent compound in combination with 10% to 50% of an alkalinematerial selected from the group consisting of sodium and potassiumchain polyphosphates, silicates and combinations thereof, together with0.25% to 2% of a polymer of isobutylene and maleic anhydride,cross-linked by reaction with ethylene diamine, the said cross-linkedpolymer having a viscosity of from 100 to 10,000 centipoises.

10. An aqueous liquid detergent gel consisting essentially of 40% to 65by weight of water and 5% to 25% of a synthetic, non-ionic, organicdetergent compound in combination with 10% to 50% of an alkalinematerial selected from the group consisting of inorganic sodium andpotassium chain polyphosp'hates, silicates and combinations thereof,together with 0.25% to 2% of a polymer of ethylene and maleic anhydride,cross-linked by reaction with ethylene diamine, the said cross-linkedpolymer having a viscosity of from 100 to 10,000 centipoises.

-11. A phase stable detergent composition having the followingapproximate proportions as parts by weight:

Condensation product of 8.5 moles of ethylene oxide with 1 mole oftridecanol 15 Potassium tripolyphosphate 30 Carboxymethylcellulose,sodium salt, 0.7 degree of substitution 1.5 Sodium salt offormaldehyde-cross-linked hydrolyzed polyacrylonitrile 1.0 Water 52.5

12. A phase stable detergent composition having the followingapproximate proportions as parts by weight:

Condensation product of 8.5 moles of ethylene oxide and 3.0 moles ofpropylene oxide with 1 mole of 13. A phase stable detergent compositionhaving the following approximate proportions as parts by weight:

Condensation product of 8.5 moles of ethylene oxide with 1 mole oftridecanol 13.5 Isopropanolamide of lauric acid 1.5 Potassiumtripolyphosphate 30.0

Carboxymethylcellulose, sodium salt, 0.7 degree of 2,645,615

substitution Sodium salt of formaldehyde-eross-linked hydrolyzedpolyacrylonitrile 1.0 339 373 Water 52.5 5 9 430 650,222

References Cited in the file of this patent UNITED STATES PATENTS 10Pollok July 14, 1953 FOREIGN PATENTS France Oct. 4, 1943 France Apr. 24,1944 Great Britain Feb. 21, 1951 OTHER REFERENCES Schwartz and Perry:Surface Active Agents, Interscience Publishers, Inc., N.Y. (1949), page204.

1. AN AQUEOUS LUQUID DETERGENT GEL CONSISTING ESENTIALLY OF 40% TO 65%BY WEIGHT OF WATER AND 5% TO 25% OF A SYNTHETIC, NON-IONIC, ORGANICDETERGENT COMPOUND IN COMBINATION WITH 10% TO 5% OF AN ALKALINESUBSTANCE SELECTED FROM THE GROUP CONSISTING OF SODIUM AND POTASSIUMCHAIN POLYPHOSPHATES, SILICATES AND COMBINATIONS THEREOF TOGETHER WITH0.25% TO 2% OF A CROSS-LINKED VINYL POLYMER HAVING A VISCOSITY OF FROM100 TO 10,000 CENTIPOISES.